1. Technical Field
The present application relates to a lighting device, and more particularly to an LED bar lighting with a uniform illumination.
2. Description of the Related Art
Light emitting diode (LED) is growing in popularity due to decreasing costs and long life compared to incandescent lighting and fluorescent lighting. Recently, a number of LED lighting apparatuses have been designed to replace the halogen apparatus, as well as other traditional incandescent or fluorescence lighting apparatuses. In some places such as exhibition halls, jewelry stores, museums, supermarkets, and some home lighting, such as large villas, will use a lot of strip LED lamps. Moreover, in addition to lighting equipments, such as general traffic lights, billboards, motor-lights, etc., also use light-emitting diodes as light source. As described above, for the light-emitting diodes as a light source, the advantage is power saving, and the greater brightness. Therefore, the use has been gradually common.
With the use of the large number of LED lamps, especially LED bar lightings, the real requirements of user is further closed in home or business areas of the lighting. However, the LED chip used in the LED bar lighting is close to a point light source so that it is difficult to obtain a uniform illumination on the luminous area illuminated by the LED bar lighting. Generally, the middle of the luminous area is strong brightness and both sides thereof are dark, which make the luminous area not beauty. Now, one solution is to increase the number of the LED chips, such as setting two rows of LED chips, or more rows. However, this method increase the cost of the entire LED lighting, especially in some occasion, it is no need so much brightness. Only for obtaining uniform illumination to increase the cost and manufacturing difficulty, it will often lose the competitiveness of the LED bar lightings.
Therefore, it is necessary to provide an LED bar lighting with a uniform illumination which makes it possible to decrease the cost.